Power converters including a power module such as a MOSFET disposed on a substrate are known (for example, JP 2013-26010 A and JP 2008-113509 A).
Such a power converter 100A includes transistors Q1 to Q4, a thermistor element TH for measuring the temperature of a substrate X, a temperature detection unit TDC for detecting the temperature of the thermistor element, a voltage detection unit VC for detecting the voltage of a resistor RI, and a control unit CON for controlling the transistors Q1 to Q4 (FIG. 6).
The thermistor element TH is disposed on the substrate X together with the transistors Q1 to Q4. One end of the thermistor element TH is connected to the temperature detection unit TDC via a node ND1 of the substrate X, and another end of the thermistor element TH is grounded via a node ND2 of the substrate X (FIG. 6).
A temperature corresponding to the resistance value of the thermistor element TH is detected based on the voltage detected by the temperature detection unit TDC.
The conventional power converter 100A described above needs to have the independent two nodes ND1 and ND2 on the substrate X in order to detect the voltage of the thermistor element TH on the substrate X.
This causes a problem in the power converter 100A in that manufacturing costs may be increased due to an increase in the number of nodes (the two nodes ND1 and ND2 in FIG. 6) of the substrate X used to detect the voltage of the thermistor element TH on the substrate X.